. >> reporter: a few years back when the hunt for osama bin laden was still raging, some intelligence forces believed al qaeda was even developing its own intranet that was electronically hidden behind jihadi websites and accessible to only a few people. whether they succeeded or such a system still exists like much of the communication structure remains shrouded in mystery. tom foreman, washington. >> of course the great irony using so much american innovation to try to destroy america. >>> our tourt fourth story outfront, dr. sanjay gupta changes his mind on weed. 20 states allow medical marijuana. and the medical community seems to be changing its mind on pot. but you know, not everybody is. a lot are adamantly against it. but there is a dramatic turn around for dr. gupta who just four years ago wrote an article for "time" magazine titled why i would vote no for pot. the ground breaking new documentary airing this sunday on cnn. and in it, he explained why he changed his mind. sanjay, the fda says marijuana is harmful, we know that. michael bloomberg is quoted saying medical mariju